This research program will continue investigations into naturally occurring food toxicants of importance to both animals and man. The toxins under consideration come from fungi that contaminate foods, from normal metabolites of food plants, and from stress metabolites induced by mechanical and chemical injury, or by fungus infection of the plant. Main emphasis will be on the liver and lung toxic factors from the common sweet potato (Ipomoea batatas). Biochemical mechanism of action studies on both classes of toxins will be continued in order to elucidate the enzymatic mode of toxin "activation" by host cells and the binding of the activated species to target cellular components. This work will be coupled with pathogenesis studies relating biochemical events to morphological changes during development of the toxic response. Consideration also will be given to ascertaining the carcinogenic potential of sweet potato toxins as elicited by mutagenicity for bacterial test systems and, if indicated, long term feeding of toxin to laboratory animals. Pathogenesis of the lung toxin for bovines will also be studied. Collaborative arrangements have been made with health authorities in Goroka, New Guinea to determine whether any relationship exists between prevalent lung disease in Highland natives and their heavy consumption of sweet potatoes.